SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d3da704b5ba393cbf15a4558d748547b8f772ec4d5ada54bc55849aaa41fb21' 
  AND token = 'iq9vg7aViMJuwX9qNGCPJbvpAZPcRQrmdqnbbXPFnXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}